/Engine/Source/Runtime/SlateCore/Public/Fonts/CompositeFont.h
Append a new font into this family
[FTypeface](API\Runtime\SlateCore\Fonts\FTypeface) & AppendFont ( const [FName](API\Runtime\Core\UObject\FName) & InFontName, [FString](API\Runtime\Core\Containers\FString) InFontFilename, const EFontHinting InHinting, const EFontLoadingPolicy InLoadingPolicy )